1) Field
Embodiments of the present invention generally relate to plasma processing equipment, and more particularly to methods of controlling temperatures during processing of a workpiece within a plasma processing chamber.
2) Description of Related Art
In a plasma processing chamber, such as a plasma etch or plasma deposition chamber, the temperature of a chamber component is often an important parameter to control during a process. For example, a temperature of a substrate holder, commonly called a chuck or pedestal, may be controlled to heat/cool a workpiece to various controlled temperatures during the process recipe (e.g., to control an etch rate). Similarly, a temperature of a showerhead/upper electrode or other component may also be controlled during the process recipe to influence the processing (e.g., etch rate uniformity).
Often, various constraints on design of a plasma processing chamber necessitate introducing a heat transfer media to a temperature controlled component in a manner which results in heat transfer within portions of the component that are not desired. For example, where a process gas distribution showerhead or workpiece chuck has a plurality of zones which can be independently controlled to separate setpoint temperatures or to better manage disparate heat loads between the zones, a heat transfer media utilized for control of a first temperature zone (i.e., a target zone) may also pass proximate to a second temperature zone (i.e., a collateral zone) en route to, or from, the target temperature zone. As such, driving the plurality of temperature zones independently can introduce significant cross-talk between the zones as well as significant temperature non-uniformity within the collateral zone.